The rust race
The question
What makes iron rust fastest, and how should museums store iron meteorites?
Iron meteorites rust if they get damp, especially if salt gets in. Collectors and museums keep them dry to stop this.
Equipment
- Five identical iron nails (not stainless or galvanised)
- Five clear jars with lids
- Tap water, salty water, cooking oil and a packet of silica gel from a shoebox
- Labels and a camera
Method
- Jar 1: nail in tap water. Jar 2: nail in salty water. Jar 3: nail half in water, half in air. Jar 4: nail covered in oil. Jar 5: nail with silica gel, lid on tight.
- Label the jars and photograph them on day one.
- Look at the nails every day at the same time for one to two weeks and photograph them.
- What to measure
- A rust score from 0 (no rust) to 5 (covered in rust) for each nail each day.
- How to present it
- A line graph of rust score against time for each jar, your daily photos, and advice for storing an iron meteorite.
- Take it further
- Find out why some iron meteorites keep rusting even when dry: chlorine from the ground can get into them and make them weep.
Safety
Do not drink or taste anything. Throw away the jars and nails with an adult when finished, and wash hands after handling rusty nails.